Child resistant packaging is a great concept for preventing children from opening potentially dangerous materials such as medications, but for adults, especially the elderly, such packaging can be a nuisance. However, simply making the contents of the package more easily accessible to the elderly bears with it the risk that the contents could be accessible to children who could be injured if they obtain access to the contents of a package and ingest the contents contained therein.
Attempts to deal with the aforementioned problems are disclosed in the patent literature. For example, U.S. Pat. No. 3,993,208 issued to Ostrowsky on Nov. 23, 1976 discloses a safety closure means wherein the shoulder on a container is formed with a pair of diametrically positioned locking lugs. The mating closure is formed of thermoplastic material and has a top end wall and a depending annular inner wall in addition to a depending outer annular skirt spaced from the inner wall. The inner wall includes threaded means for engaging the neck of the container to secure the cap to the container in a closed position. The outer skirt of the cap has a pair of diametrically positioned radially extending locking lugs adjacent the lower end of the skirt. The cap locking lugs are adapted to pass inwardly of the container locking lugs and to be compressed radially inwardly when the cap is rotated to a cap closing position. As the cap lugs move past the container locking lugs, the cap lugs are released from their compressed condition so that they extend outwardly beyond the engaging edges of the container locking lugs. This prevents the closure from being unscrewed until the outer skin of the closure is manually squeezed radially inwardly adjacent the cap locking lugs to permit them to clear engagement with the edges of the container lugs as the cap is unscrewed from the container.
Under normal in use conditions, removal of the closure of Ostrowsky requires squeezing the outer skin of the closure sufficiently to disengage the lugs on the container and simultaneously unscrewing the closure with the same hand used to apply the squeezing force. This may be difficult, particularly for elderly persons who may have impaired manual dexterity and strength.
In addition, the closure of Ostrowsky visually reveals how the interlocks must be overcome in order to remove the closure. A child having sufficient strength to depress the closure skin may have sufficient intellect to defeat the interlock and remove the closure.
Another prior an attempt to overcome the aforementioned problems is disclosed in commonly assigned U.S. Pat. No. 4,948,002 issued to Thomock et al. on Aug. 14, 1990. The Thornock et al. patent discloses a package comprising a bottle, a collar which is secured in place over the uppermost portion of the bottle and a closure which is secured to the finish portion of the bottle by means of complementary screw threads. The collar preferably includes a pair of spring-like pushtabs containing vertical extensions which engage interlocking teeth on the innermost surface of the closure skin when the closure skirt is fully assembled onto the bottle. To remove the closure, the opposed pushtabs must be manually depressed prior to applying unscrewing torque to the closure to disengage the pushtab extensions from the interlocking teeth on the closure. While the Thornock et al. patent discloses a package exhibiting highly improved child resistance without significantly impeding access by adults, the disclosed collar arrangement creates an element which must be secured to the finish portion of the bottle adding to the overall cost of this package and a assembly operations needed to produce the package.
Closures such as those mentioned above are satisfactory in sealing non-flowable solid product, i.e. tablets or capsules. The sealing is done by a flat seal atop the bottle finish. After the closure is secured into place and the child resistant feature is latched, it is desired to have the closure such that it can be turned in the off direction for a small distance, without activating the child resistant feature, causing a gap to form between the bottle finish and the portion of the cap which is supposed to seal the container. This gap is typically the result of an intentional design feature, that is providing some "over-travel" or "bypass" of the closure, defined as the radial rotation of the cap past the engagement of the push tabs, i.e. the point where the tabs ride over the cap lugs, and cause an audible click. This bypass is useful and necessary since the package will tend to jam if the tab engagement position is closely proximal to the point at which the cap liner seals the bottle finish. This problem will be exacerbated by typical molding tolerance variations of the cap and/or bottle finish as well as cap liner thickness variations. Without a bypass design, the cap may seal the finish before engagement with the tabs, resulting in a package which will not close. Conversely, the tabs may engage well before the bottle is sealed resulting in a package which may leak when filled with liquid or powder products.
Accordingly, it is an object of the present invention to provide a package having a child resistant feature which is resistant to opening by the majority of children coming in contact with the package and which at the same time can readily be opened by adults who may have impaired manual dexterity in their fingers due to conditions such as advancing age, arthritis, etc.
It is another object of the present invention to provide such a package wherein the cap can rotate onto the package past the engagement of the child resistant feature, and provide for adequate sealing of the cap onto the closure at or before engagement of the child resistant feature so as to accommodate liquid or powder products.
It is another object of the present invention to provide a package having a child resistant feature wherein the child resistant feature is integrally molded into the bottle such that the child resistant feature of the bottle is complete in a single operation without the need for any further assembly operations to secure the child resistant feature to the bottle.